1. Field of the Invention (Technical Field)
The presently claimed invention relates to tools and more particularly to tools for demounting tires from wheel assemblies.
2. Background Art
There is a large variety of hand operated and power assisted tire demounting tools on the market. They range from simple pry bars to geometrically complex leveraging devices, along with power operated demounting devices. With the wide range of composite materials, sizes, bead shapes, and methods of manufacture for tire and wheel assemblies, there are a number of inherent limitations to the current methods and apparatuses for tire demounting. These limitations range from functionality to adaptability. They fail to address some key factors in the successful removal of a tire from the rim or wheel assembly.
The functionally of the prior art systems for demounting tires is limited in a number of ways. Many conventional pry spoons and bars are made with a narrow design in relationship to the tire bead. This results in damage and tearing of the tire bead while trying to remove the tire from the wheel. The construction of low profile tires also is a limiting factor for many of the current tools. These low profile sidewalls and the use of multi-ply steel or fiber construction, make these tires stiff and difficult to work with. Current power operated devices, which typically work in a concentric motion, tend to tear and ruin the bead of these types of tires. Hand tools often prove ineffective, having neither the shape to conform to such tires or sufficient prying force to extract them from the rim or wheel. Removal of these tires with the current devices results in damaging the tire beyond repair thus, defeating the purpose of repairing and remounting the tire.
A further limiting factor for many of the current tools is the removal of soft side wall tires with a highly pliable bead. These tires present the problem of having a bead that stretches, but becomes difficult to extract from the wheel. The highly pliable bead will typically be pried above the rim only in the area directly engaged by the tool or pry bar. Disengaging the tool from this area will cause the elasticity of the bead to return to its original position, thus failing to remove the tire from the rim. The narrow hand operated spoons and pry bars are especially susceptible to this malfunction and there is often the added consequence of bead tearing.
Another limiting factor for many of the prior art methods is a failure to address the demounting of what are referred to in the industry as “super single” sized tires. These are extra wide wheel assemblies with their corresponding extra wide tires. Being extra wide in their construction, these type of tire and wheel assemblies pose a problem for the current methods of demounting, often rendering most of these methods completely ineffective, because they cannot accommodate this size of tire. The current methods available to accommodate these types of tires are exclusive solutions made for the specific purpose of removing these tires from their wheel assemblies and therefore not multi-functional.
Finally, these prior art methods, whether power or hand operated tire demounting systems, work on one of two principles which further limit their effectiveness in removing a variety of tires from a variety of rims. The power operated tools almost exclusively work on the principle of concentric motion having a demounting armature that is engaged between the rim and bead and is then rotated around a central axis three hundred and sixty degrees (360°) or until the tire bead is dislodged from the rim by the demounting device. This concentric motion causes severe stretching and even tearing of the bead because this method does not work in accordance with the construction of tire and wheel assemblies as a whole. These power operated tools also fail to address the range and variety or tire and wheel assemblies because they are limited to fixed sizes. The hand operated tools work exclusively with a leverage of motion principle. This basic principle of the hand operated tools limits their range of motion by the leveraging stroke, rendering this method inadequate for the extraction of a tire from the rim. Further, some wheel assemblies have “a reverse wheel”, which have the main part of the hub center offset to the top of the demounting side. The placement of the hub center further limits the leveraging stroke of the current hand operated pry bar tools to such a degree that they are ineffective. The hand operated tools of complex geometry are further limited in the variety of tire and wheel assemblies they will work on, often being constructed for exclusive sizes and shapes of tire and wheel.